Good luck, A_1.
I've just been through this job (but without the HDD swapouts) only yesterday.
Bought a new slim PS3 so the kids can play on "the big TV" during the day, but I can still have the option to play either on "the Big TV" or in my office area when mummy's watching TV on "the big TV".
Big TV gets new slimline, My office has original 60GB, everyone has their same profiles, everyone is happy.

Unless you play Little Big Planet. (Which I know you don't, A_1 (I checked ), so you're OK)
Which is a Little Big Problem in my house, because all my kids have customised sackpersons, etc.

Some types of data cannot be transferred using the data transfer utility, and some types of data can be transferred but not played on the destination PS3 system.
For the latest information, visit the support site for the data transfer utility. The following types of data are not transferrable:

Video content that has been downloaded as a rental from PlayStation Store (file type: MNV).

Tracks (including SongPacks) for SingStar software that have been saved on the PS3 system’s hard disk.

Game data from LittleBigPlanet.

Copyright-protected video files (file type: MGV).

Video files that are compatible with the DivX® VOD (Video On Demand) service.

* Official PlayStation Magazine
For the following data types, you must perform some additional steps after completing the data transfer to be able to use the data:

Application data for Life with PlayStation®

Download and install the Life with PlayStation® application on the destination PS3 system. You can continue using your contribution points for the PlayStation Network ranking system of the Folding@home™ channel.

GripShift

When you start the game for the first time after the data transfer operation, an error message will be displayed and you will not be able to play the game. To play the game, download and install the game again.

Saved data for Ghostbusters and Ghostbusters: The Video Game

The saved game will not be recognised when you start the game for the first time after the data transfer operation. To use the saved data, quit the game, and then start the game again.

The first is an iomega 1TB fixed unit.
The second is a unit which allows 2.5 and 3.5 HD's to be slotted into it.

The first unit had a large number of files requiring transfer firstly to one of our main computers. Then we tried to formate the HD from NTFS to fat 32 and swissknife would not allow it. No matter what we tried it refused to allow us to make the HD in iomega a 32 fat file system.

The second unit allowed us to format the 3.5 250GB HD easily with swissknife to 32 fat file system. We then put it to work on backing up PS3 Old overnight.

Then I remembered we still had the 2.5 120GB original HD from the slim. So this morning I managed to format this and it's currently backing up the slim now.

We are now delayed by the fact it took so long to get both units backed up and by the fact later today backup and restore functions will be through one external HD unit, Steps Four and Steps Seven.

As you know if you don't want to loose any content it takes 2 - 4 hrs per backup depending on the size of the HD.

Progress has been slow to say the least. The backups were completed by 10am.
We then manually copied the save files for 2 accounts from the slim to a USB flash drive.

This is very painfull given that you have to do each save file 1 by 1. This and the fact we realised Assassins Creed II is protected content. I sacrificed this save file to allow my son to transfer his 5 Protected Content files to the slim.

At 11:30am we started the PS3 Old to PS3 Slim transfer. It's now 4pm and after 4hrs 30min we still have around 1hr to go according to the timer.

It appears this will not be a single day process.

Please Note: when doing this sort of thing delete all content you don't want to save. It will speed up the whole process that much more quicker. My son wants everything, game demo's, music, trailers etc etc. 200GB worth of (shit). Don't you get caught in the trap.

This morning I swapped out the HD's which only took 10min. Very easy to do once you have done it once before. Step Five complete.

Step Six issues:

PS3 Old was perfect. Recognised the HD suggested I format it then booted into the XMB. The PS3 Old retains the firmware as it has more flash RAM then the slim.

PS3 Slim was a pain. PS3 slim required the firmware to be available before it would format the HD. It had issues with my USB flash drive but we had a few on hand so was able to finally overcome the problem. The HD was formatted and then the Firmware installed.

Step Seven:

PS3 Old took around 2 hrs to restore the contents. 80GB backup image, 111GB of content.

PS3 slim is still restoring after 6hrs but all looks good so far.

Step Eight completed on the PS3 Old. Will complete Step Eight on the slim later tonight but I don't expect any problems.

Well I have to say it's been fun and it was interesting to see some of the major differences between the older and newer machines.

I think I prefer the older machine overall but that is obviously my own opinion.

Hope this helps anyone else who might be considering a similar upgrade.

purchased a new PS3 slim today. was going to replace the hdd in the old PS3, then thought, stuff it; just get a new console.
have no idea what i'm supposed to do first, when it comes to setting up the new one & transferring all the data ect from the old PS3

so far all ive done is copy game save data onto 3 USB sticks. but there's more things i want to keep, ie-- some inbox messages & photos.

1. Sync your trophies to PSN.
2. Disable the wifi connection on the old PS3.
3. Switch off.
4. Connect PS3 Old to PS3 Slim via a network cable.
5. Switch on both machines.
6. Tell PS3 Old to transfer to other system.
7. Tell PS3 Slim to transfer from other system.
8. Go and get a beer as this will take some time depending on the amount of stuff to transfer.

Notes:

1. This will go more smoothly if you have both machines connected at the same time to the one TV. You can just switch between the channels to view the steps your taking.

2. All content on the old will be copied to the new.

3. All protected content will be transfered permanently to the new and deleted from the old.